In the previous session the musketeers of the Royal Homeland Constabulary traveled to Axis Island. Originally their role was to be a backup team for another team of infiltrators, but the first team got killed very early in the mission and the player group had to take over. This session began with them traversing an underwater tunnel and reaching a sea cave at the bottom of a mine.

The sea cave was 60 feet high, with the exit being 35 feet above sea level. A series of platforms and ladders was leading up, and right when the group entered and made light the avenger (with his 21 passive perception) noticed a shadow on one of the upper platforms moving towards the tunnel. The group left the water and started climbing up those ladders, when they were attacked by a Danorian mine foreman, who had an earth elemental and a shadow elemental as allies. The foreman was very excited and accused them of having killed his miners.

Now the combat wasn't designed to be epic, but in my opinion it was over too quick. I guess the adventure is optimized for 5 characters, and my player group has 6. I don't want fights to drag on forever, but 13 hit points for the shadow elemental was clearly too low. It isn't much use to have monsters with interesting abilities if those monsters die on turn 1 and never really get to use them. The earth elemental was doing better, but in the end the group prevailed with just some minor wounds. They knocked out the foreman using non-lethal damage and searched him. That resulted in them finding two gold icons (medallions) which were magic. A third gold icon was found in the sea cave in a white marble pillar. The icons had different symbols and affinities to different elements.

After reviving the foreman the constables questioned him. Risuri forces, apparently the duchess' men, had killed his team of miners and he was the only survivor. They asked him how to get out of the mine, and he boasted how in Danoran mines the exit was clearly indicated at each fork of a tunnel. They tried to convince him that they were friends, trying to give back the island to Danor, but that story (while true) didn't really convince the foreman. Curiously the group not only decided to let him go, but also returned one of the three gold icons to him, as its power to become insubstantial for one round didn't appear very powerful to them. Heroes giving away magic items was not something the adventure had foreseen as possibility, so it remains to be seen how important the golden icons become in the rest of the campaign.

Following the exit signs the musketeers left the mine and found themselves in the middle of Axis Island. A small mountain range separated them from their target, the only fortress of the island, so they could go either on the road around the mountain, or directly over the mountain. As that was only about a mile of distance and more discreet, they decided to take the direct route. On the way they encountered some of the strange phenomena Axis Island is known for: Flames erupting from the tops of trees, and a reality fluctuation that transported them for a few seconds to a different world with a purple sky and blue sun; that was the same phenomenon that had preceded the cave-in that had killed the first infiltrator team, but in this case it caused only a minor landslide. The group also encountered an iron golem, who apparently had lost his head in a battle and was staggering aimlessly through the forest. Aria the spirit medium heard thousands of spirit voices coming from the golem, and the oil trace that he left.

The group was in a very determined mode, and didn't investigate the strange phenomena or golden icons any further, but pressed on towards the fortress. They arrived at the fortress wall, which was only lightly guarded with a patrol passing every 10 minutes. As planned they got through the weak spot in the wall with the help of a passwall scroll. From there they sneaked through the outer fortress towards the harbor. They passed by a prison, but as that one was well guarded they abandoned a first idea to free the prisoners. By taking the shortest way they only had to make one stealth check, and only failed 2 checks, raising the alarm to mild level. With several characters in heavy armor and having negative stealth check modifiers, that was as good as they could hope for.

Arriving at the harbor they had a good view of the sea wall, which was guarded, and the lighthouse. Aria proposed using another water breathing scroll to get to the lighthouse discreetly under water, which is what they did. As it was getting late and the events at the lighthouse will require some time, we stopped the session there.

It would seem as though the state of urgency you've created means they are ignoring everything that isn't on the main path. They are missing out on the side-content that could provide lore, alternative solutions, power boosts or hints because they are concerned it will delay them from the main quest.

Are you suggesting that they have time to choose at least one side-quest without risking messing up the main. A time-locked door (lighthouse only accessible in 2 hours time when the tide has gone down or a guard roster showing they'll be changing in 90 minutes), lets them opt to do some exploration without feeling you will overly punish them for that choice. The down side is that can lead to a story that goes hurry-hurry-wait-hurry.

Also, are the dimension shifts and the magic item hinting that they should be looking to use those abilities (though one has now been lost and the other is unreliable) to perform a limited dungeon bypass through a wall?